Electric control apparatus



March 19445 H. F. ELLIOTT ELECTRIC CONTROL APPARATUS Filed July 21, 1941 6 SheefiS-ShGGt 1 March 7, 1944. H. F. ELLIOTT ELECTRIC CONTROL APPARATUS Filed July 21, 1941 6 Sheets-Sheet 2 March 7, 1944. ELLlOTT ELECTRIC CONTROL APPARATUS Filed July 21, 1941 6 Sheets-Sheet 3 ugu up EEFTF March 7, 1944. H. F. ELLIOTT ELECTRIC common APPARATUS Filed July 21, 1941 6 Sheets-Sheet 4 March 7, 1944. H F. ELLIOTT 2,343,540

ELECTRIC CONTROL APPARATUS Filed July 21, 1941 6 Sheets-Sheet 5 km 1/ 5W :1

- fizar 163 March 1944- v H. F. ELLIOTT A 2,343,54

ELECTRIC CONTROL APPARATUS I Filed July 2 l, 1941 6 Sheets-Sheet 6 v /zya/zfarflaw/J 2:7 mm 4 w Patented Mar. 7, 1944 UNITED STATES PATENT OFFICE anac'rarc CONTROL mana'rus. Harold F. Elliott, Palo Alto, Calif. Application July 21,1941, Serial No. 403,450

7 18 Claims. (01. 250-20) This invention relates in general to control apparatus and more in particular to electric tuning apparatus for a radio receiver.

It is an object of this invention to provide improved electrically-operated control apparatus which can be readily applied to many types of controllable mechanism including automobile radio receivers and radio receivers for home use.

A further object of this invention is to provid a compact, simple, and inexpensive electricallyoperated control apparatus which is comprised of a minimum of readily available commercial parts adapted to be pre-assembled into a unit which operates with precision and emciency.

.Anotlier object of this invention is to provide a tuning device for a radio receiver in which a plurality of inductance units are adapted to be set in a predetermined matched relation at-each desired tuning position by means capable of also retaining such relation during the usual operation of the device.

Yet another object of this invention is to provide a tuning device in which inductance tuning means are complemented by capacitance tuning means at each desired tuning position by an amount sufficient to compensate for the inaccuracies in inductance tuning at such tuning position.

Another object is to provide a radio tuning device in which inductance tuning means is complemented by capacitance tuning means in a predetermined relation at a plurality of tuning positions, the relation being maintained in the normal operation of the tuner by means including a common operating member for such inductance and capacitance tuning means.

A still further object is to provide electric control apparatus which operates very quickly and positively, and which is simply adjusted to various predetermined control positions without the use of special tools or the like.

A particular feature of this invention is found in the provision of a plurality of inductance tunthe movable plate being adapted to be continuously moved relative to the fixed plate during operation of the control apparatus with which it is employed so as to continuously vary the capacity of the condenser.

A feature of this invention isthe provision of electric tuning apparatus for a radio receiver in a pre-assembled unit which can be completely assembled and tested under operating conditions before it is ever assembled into the receiver.

Another feature of this invention is the provision of adjustable control structure which includes a plurality of axially mounted rings having only a mechanical function in the operation of the control structure, and being individually adjustable independent of other rings in the structure.

A further feature of this invention is the provision of a cooperating latch for each of the control rings in the control apparatus which is of a flat construction and adapted to be flexibly movable in a direction substantially at right angles to the plane thereof, while rigidly secured at one ing units having core elements adapted to besimultaneously moved by a common driving member toa' plurality of tuning positions, with each of said elements being operatively associated with a corresponding adjustable cam means which acts to individually adjust each core independently of the relation therebetween as established by their connection with the common driving member.

Another feature of this invention is found in the provision of a variable condenser unit ineluding a fixed plate and a movable plate, with end.

A still further feature of this invention is the provision of a simple clamping mechanism for varying the friction on the control rings in the control apparatus of the invention to permit their individual angular adjustment and likewise maintain them positively fixed in an adjusted position.

A still further feature of this invention is found in the provision of a timing urilt having frame means integrally formed with a base and side members, with all of the elements of the tuning unit being operatively arranged entirely within the confines of such base and side walls and completely supported thereon.

Another feature of this invention is the utilization of the tuning motor of the tuning device for a radio receiver in operating the power supply switch for such receiver.

Further objects. features and advantages of this invention will appear from the following description when taken in connection with the accompanying drawings in which:

Fig. l is a sectional plan view of one embodiment of the invention as seen along the line l-l in Fig. 3 showing the assembly relation of inductance tuning units, a control member and the control mechanism for operating the control member;

Fig. 2 is a side view as seen along the line 2-1 in Fig. 1 showing the cam means associated with round in each of the inductance units for individually adjusting the same;

Fig. 3 is an end view looking toward the right as viewed in Pig. 2 showing the assembly rela- Fig. 3 is a fragmentary sectional view of a modified form of adiustable cam means for the inductance units in the embodiment of Fig. 1;

Fig. 9 is a circuit diagram for the tuning unit of Fig. 1;

Figs. 10 and 11 are schematic views illustrating a control ring and associated latch in changed operating positions;

Fig. 12 is a plan view of a modified form of the invention:

Fig. 13 is an enlarged end view of a condenser unit employed in the unit of Fig. 12, as seen along the line l3l3 in Fig. 12;

Fig. 14 is a fragmentary sectional view of the condenser unit as seen along the line l4-l4 in Fig. 13;

Fig. 15 is a sectional view taken along the line ll-ll in Fig. 12:

Fig. 16 is a fragmentary end view looking along the line lO-l' in Fig.15;

Fig. 17 is a fragmentary plan view showing the assembly arrangement of the magnets and armatures used in the unit of Fig. 12;

Fig. 18 is a sectional view taken on line l3-l3 in Fig. 12 with parts thereof being broken away for the purpose of clarity; and

Fig. 19 is a schematic diagram showing the electrical control circuits for the tuning device of Fig. 12 and for a radio receiver with which it is employed.

In the practice of this invention there is provied a tuning unit for a radio receiver having unitary frame means comprised of a base and integrally assembled end and side plate members. A rotary control member is supported for rotation in the end plates and is operatively connected near one of its ends with control mechanism therefor. The tuning circuit for the radio receiver includes variable tuning means operatively connected with the control member near the other end thereof, the tuning means, control member, and the control mechanism being entirely within the confines of the end plates of the frame means. The control mechanism includes a control member or ring assembly which is electrically operated by selectively actuated electrical means and adapted to rotate the control member to control positions corresponding to predetermined tuning positions. The variable tuning means in the tuning unit may be either of inductance or capacitance type or a combination of both types. When inductance tuning alone is employed there is provided aplurality of inductance units having core elements simultaneously movable to a plurality of tuning positions by a common driving member, but each of which is acted on by a corresponding cam means so as to be individually adjusted to different relative positions at each tuning position. Such individual adjustment of each core of the inductance units provides for a predetermined matching of the inductance units in the tuning circuit over a complete range of frequencies. Where assauo inductance and capacitance tuning are used together. the capacitance tuning means is adjusted in a complementary relation with the inductance tuning means at each of the selected station frequencies to provide for predetermined tuning characteristics of the tuning circuit over a desired frequency range. Both of the tuning means are concurrently driven by a rotary control member, the effective inductance and capacitance in the tuning circuit being varied simultaneously and in accordance with the predetermined adiusting thereof to retain their complementary tuning relation.

With reference to the drawings the invention is shown in Figs. 1-4 as including frame means 2| having an integrally formed base 2| and side plates 22 and 22a, with the end portions of this integral structure being-provided with inwardly extending flanges 23. Each end plate 23 and 23a of the frame means 20 is fitted between the side plates 22 and 22a and against the flanges 23 for securement thereto as by welding or like means. It is thus seen that the frame means 20 is of a rigid and unitary construction so that any relative loosening between the parts thereof is completely eliminated.

Extending longitudinally of the frame means 23 is a rotary control member 21 which is rotatably supported at one end in the end plate 280 by a bearing member 23 and at its opposite end 25 in the end plate 23 by hearing means 22, the assembly of the bearing means 23 and 23 in the -end walls 23a and 28, respectively, being such that the control member 21 is completely positioned therebetween. The control member 21 at its end 25 is provided with a cylindrical body portion 3i having hub portions 33 and 34 of difierent diameters separated byan annular flange 32. As is clearly illustrated in Fig. 1 the fiange 32 is arranged intermediate the ends of the body portion II, with hub portion 33 being positioned toward the end wall 26. A control member unit 33, to be later fully exp ained, and which forms a part of the control rne hanism designated generally as 31 for the rotary control member 21, is adapted to be mounted on the hub portion 33 and against the flange 32. Mounted for slidable movement on the hub portion 34 is a sleeve or bushing member 38 integrally formed with spaced radially extending driving arms 33 and a radially extending guiding arm 4| arranged between a pair of adjacent ones of the arms 3| (Fig. 4). The hub portion 34 is formed in the periphery thereof with spaced spirally extending grooves 42 which are adapted to receive in following engagement a corresponding ball portion 43 seated in a recess or opening 44 in the sleeve or sliding member 38. Each ball 43 is retained in a corresponding recess by one end 48 of a spring 41 which is of flat form and bent at-a substantially right angle. The spring at the bend therein is secured by a rivet 40 to an inner portion 45 of a corresponding arm 33. (Fig. l.) The guiding arm 4| (Fig. 4) slidably engages one side of a driving and manual control shaft 43 which extends longitudinally of the frame means in a parallel relation with the control member 21 and is rotatably supported in the end plates 23 and 26a. The guiding arm 4| has a flat spring member 49 for slidably engaging an opposite side of the driving shaft 43, which serves as a guideway for the driving member 33. It is evident, therefore, that on rotation of the control member 21, the sleeve or driving member 33 is retained against rotation by the coaction of the guidingarm 4i and its associated spring 49 with the shaft 49. However, since the ball portions 4: follow the spiral grooves 42 the sleeve 99 is slidably moved on the hub portion '34 in a direction axially of the control member 21, the-- guiding arm 4| and spring 49 in turn being slidably moved along the shaft 49. This linear translation or movement of the sleeve 30 in response to a rotation of the control member 21 is utilized in moving the adjustable core elements 49 of the inductance tuning units Bic-Bic to their tuning positions as will now be fully ex- 99 is the same, only the assembly for the inductance unit Sic will be referred to in the following description.

As shown in Fig. l, the core 49 is arranged for adjustable movement in a direction axially of the control member 21 and within its corresponding coil 52. Thus by connecting the free end of the core 49 to the arm 99 the core may be moved to a tuning position in direct response to a rotation of the shaft 21 by virtue of the sliding ofthe sleeve 98 axially of the shaft 21. However, in the tuning function accomplished by the relative motion between the core and the coil in the inductance unit 5|, it is essential that the core be placed in a correct position with respect to the coil for each tuning position so I that the effective inductance in the tuning circuit will be of a value providing for uniform tuning performance over a predetermined frequency range. Because of difficulties encountered in obtaining commercially available coils and cores of like electrical characteristics, and of establishing a precise relation between the coil and core by merely mounting the coils on an appropriately designed rigid foundation plate such as the plate 26a, it"is advisable that the core be individually adjustable with respect to its cooperating coil independently of the initial relation established therebetween through the connection of the core with its driving member which in the present invention, is the sleeve unit 39.

This individual adjustment of the core and coil is accomplished by means including a crank arm 53 which is pivotally connected by axis means 54 to the outer end of arm 39. The end Bl of the crank arm 53 is movable within an opening 51 (Fig. 4) formed in the arm 99, and is pivotally connected as indicated at 58 to the outer end of the core element 49. The opposite end ii of the crank arm functions as a follower relative to a cam surface 63 for cam means indicated generally as 82a. The crank arm end ii is retained in operative engagement with the cam surface 98 by the pressing engagement of the end 04 of the spring 41 on the core element 49. The spring 41 thus provides a resilient holding pressure on the ball portion 43 in the sleeve member 99,- and acts to minimize lost motion in the connection between the core element 49 and its driving arm 39.

The cam means 620 is comprised of a longitudinally' extending plate member 01 having transversely extending louvres or blades 68 spaced longitudinally thereof. The cam surface 63 is comprised of a plurality of flexible bands 69 composed of thin strips of bronze or like material. which extend longitudinally of the plate and over the blades 99, the end ll thereof being fixed to the plate, while the end I! is y eldably connect-' ed with the plate through a spring 14. The bands 09 are thus retained under tension against the blades 60. By deflecting the blades 99 at varying angles laterally of the plate 61, the shape of the cam surface 69 is varied. 'Any contour of the cam may thus be obtained while maintaining a continuous cam surface. The plate 61 is adapted for positioning in an opening 11 formed in the side wall 12 of the frame 20 and is secured at its ends 15 to such side wall by screws or rivets 18. With reference to Fig. 4 it is seen that the cam means 62b and flcfor the remaining two inductance units lb "and lie, re-

spectively, are. positioned in openings lib and.

'IIc, respectively, formed in the top plate I9 and base plate 2|, respectively, of the frame means I9. In order that the cam surfaces 63b and 630 be positioned at substantially right angles to their corresponding arms 39 the cam means 62b and 620 are inclined relative to their respective supporting walls.

As was previously noted the sleeve member 39 in response to a rotation of the control shaft 21 serves to simultaneously move all of the core elements 49 to relative tuning positions. However, because of the cooperating action of the crank arm 93 and the cam means 62 for each inductance unit Sic-5 lc, variations in the cam surface 03 act to retard or accelerate the movement of each core element 49 relative to each other and to the movement or the sleeve member 98. As a result of this varying speed of travel of each core element 49 while the sleeve member 38 moves at a substantially uniform speed, each core element is individually adjusted with particular reference to its associated coil. A relative positioning of each core in its respective coil for each tuning position may thus be precisely set by the cam means to provide for a predetermined matching of the inductance units at each tuning position and consequent high tuning performance over a wide frequency range. The tuning inaccuracies usually encountered in inductance tuning of this type are thus practically eliminated. It is unnecessary, therefore, that the electrical characteristics of the cores and coils constituting the inductance units be closely matched as to electrical characteristics, since variations in their electrical characteristics resulting from the usual inaccuracies in their manufacture, are entirely compensated for by the proper adjustment of the cam means 62 for each inductance unit 5la,5lc. Usual commercially available parts for the inductance units Bid-Sic may be thus readily utilized to provide at relatively low cost a tuning device having high tuning performance.

A modified form of cam means 62' which may be employed with each of the inductance units 5la5lc is illustrated in Fig. 8, and includes a plate member 68' having a plurality of screws 8i threadable therein for adjustment. The adcans means no so that a further description thereofisbelievedtobeunnecessary 'trol member assembly" is comprised of a plurality of identical control rings 82 (Fig. 7) having a separable peripheral portion 03 and a hub portion 04. The hub portion 04 is adapted to be mounted on the hub 82 and is integrall formed with spaced radial projections 00, each of which is provided with an aperture 81 and the outer ends of which are of arcuate contour for mating engagement with the inner periphery of the peripheral portion 08. Intermediate each two control rings 02 and on the outside of the control assembly at each end thereof are identical separators or friction discs ll (Figs. 1 and 6). Each disc is formed with a central opening 08, for mounting on the hub ll. and concentrically arranged arcuate slots OI and 92 which facilitate the flexing of the disc in a direction axially thereof. Angularly spaced apertures 08 in each separator correspond to the apertures 01 in the hub portion ll of a control ring 02, the hub portions 00 and separators 00 being secured to the back support or annular flange 32 against angular movement with relation thereto by means of screws ll extending through said apertures. Each screw 04 is threadably secured in a corresponding threaded aperture 00 in the annular flange 02.

The discs or separators 00 are provided in a thin flexible fibre composition material. As can be seen from Figs. 1 and 6, the screws 9| extend through the separators radially inwardly of the arcuate slots 02 so that the ring-like outer portion of each separator is adapted to flex axially slightly at the outer circumference due to the positioning of the arcuate slots 02 between the fastening screws 94 and the circumference of the disc. Although these discs positively separate the control rings 02 they do permit of a slight axial movement of the rings so as to permit the control-ring assembly to open up enough to provide for an angular adjustment of the peripheral portion 02 of each control ring relative to its cor.. responding hub portion N, and hence for an anular adjustment of the ring 82 relative to the control member 21. As previously described, the separators are all fixed with reference to the flange 32 and prevent the angular movement of the peripheral portions of the rings 82 disturbing one another during adjustment. Due to the thinness of the separators and control members, the entire control ring assembly is very narrow as can be seen in Fig.1 to in turn assist in making the entire unit relatively narrow and very compact.

In the operation of the control apparatus and after the control rings or members 02 are each set to a predetermined angular position with reference to the control shaft 21, as will be explained, the members 02 and the friction discs 00 are compressed axially as an assembly and frictionally retained against movement relative to the flange I2 and hence to the shaft 21. The necessary frictional pressure is obtained by friction mechanism which includes a screw 00 extending into a cavity or formed in the outer end at of the hub portion a. The means for rotatably s pporting the end 20 of the control member 21 is adapted to be-received in a bulged out portion 09 formed in the end wall 20, the portion 00 and the bearingsupport 2! being provided with concentric openings III and I02 which are arranged coaxially with the cavity 01. The end 00 of the hub 23 is operatively connected with the supporting means 20, this engagement and the support of the bearing 20 in the bulged out portion 00 being retained by suitable adjustment of the thrust element 08 in the bearing-20 at the opposite end III of the control shaft 21. By virtue of the aligned arrangement of the openings III and I02 and the cavity 01, the screw 00 is capable of being extended therethrough in a direction longitudinally of the axis of the control shaft 21,

' with one end thereof bearing against the bottom of the cavity 01, and the opposite end thereof projecting outwardly from the end plate 20 as shown in Fig. 1. From a consideration of Figa l, 6 and '7, it is seen that the wall or the hub portion about the cavity 91 is formed with angularly spaced slots I02 adapted to receive'in sliding engagement radially extending projections I04 provided on a threaded support I00 for the threaded member 98, the support I00 being located within the cavity 91. On rotation of the threaded member 96, therefore, the threaded support I00 is axially but non-rotatably movable within the cavity 91.

Clamping levers I01 (Figs. 1 and 5) are arranged to extend radially outwardly in a spaced angular relation from the axis of the control shaft 21. Each lever I01 has one end I00 thereof adapted to be received within a corresponding one of the slots I03 for resting support on the threaded member I 08. As illustrated the slots I03, supporting member projections I04 and clamping levers I01 are three in number. It is to be understood, of course, that any number may be provided depending upon the particular design of the control member assembly 36. The opposite end I00 of each clamping lever I08 (Fig. 5) is adapted to be inserted through a slot III formed in a gear member I I2 which is driven in engagement with the driving shaft 40 previously mentioned. The gear I I2 is mounted on the hub 83 at one end of the control assembly 30, a metal separator II3 being positioned between the gear I I2 and the outer separator disc indicated as "a, the purpose of the metal disc I I 3 being to prevent any injury to the fibre disc a by the action of the clamping levers I01. Each lever I01, intermediate the ends I00 and I09 thereof, is supported on a shoulder portion 940 on a corresponding one of the screws 04. A spring washer H4 is positioned between the lever I01 and the screw head and the lever fits loosely'around the shoulder 04a to provide for a slight pivotal action of the lever relative to the screw.

Referring to Fig. i it is seen that the slotted openings I03 formed in the wall of the cavity 01 extend from the end 00 of the hub 33 to a point within the confines of the control assembly 30. Since the threaded support I06 is axially movable over the entire length of the cavity 91. a support of the lever ends I00 thereon when it is in an innermost position is accomplished by bending such lever ends in a direction toward the bottom of the cavity 91. Thus it is apparent that the clamping levers I01 may be arranged in close proximity to the outer end of the control assembly 00, to provide for a compact assembly of the clamping levers and the control assembly 38 in a 9,848,840 .minimum of space axially of the control member As above described the separator discs 88 and the hub portion 34 of the control rings 82 are secured against angular and axial movement relative to the control member 21 by virtue oftheir being secured to the annular flange 32 by the screws 84. Thus on any application of pressure through the clamping levers I81, the circumferential portions of the discs 88 and the peripheral portions 83 of the control rings 82 are pressed together to hold them in fixed positions, with a release of such pressure permitting axial flexing of the circumferential portions of the discs 88 and hence permitting angular movement of the peripheral portions 83 of the control rings 82 therebetween. It is understood, of course, that the peripheral portions 83 are rotatable on the hub projections 88. The friction or clamping pressure is applied upon rotating the threaded member 88 in a clockwise direction for a right-hand thread, for instance, the threaded support I88 being moved axially but non-rotatably to the left, as viewed in Fig. 1, to increase the bearing pressure of the lever ends I88 against the metal disc H3 and in turn against the control member assembly. In removing friction, the threaded support 38 is rotated in an opposite direction, the spring washer I I4 acting to maintain a nominal pressure upon the ring portions 83 to hold them in position during adjustment.

Each controlring 82 is preferably formed by a punching or stamping operation, from a single piece of material. Inasmuch as the function of a control ring is purely mechanical and not electrical, it can-be provided in any material desired. The peripheral or ring portion 83 of each control ring 82 includes a high side H and a low side L (Fig. 7) each extending over slightly less than 180 to the outer surface of the ring, and separated at one of their ends by a recess R. A

- lectively energized on actuation of corresponding stop shoulder H8 is provided on one side of the I recess R at the high side H of the ring. Cooperating with each ring 82 is a corresponding latch II1 pivotally mounted on a fixed shaft H8 carried by the frame means 28. in the present embodiment six latches are employed corresponding in number to the six control rings 82 illustrated in Fig. 1. In order to provide as compact an assembly as possible and to provide adequate mounting and operating space for the latches and yet maintain the tips 8 of the latch arms III in alignment axially of the control assembly 38, the six latches are pivoted on the same shaft II8. Each armature arm I22 of a latch H1 is operatively associated with a corresponding. magnet I23 which are arranged in two parallel rows of three magnets each (Fig, l) and supported on a bracket I28 mounted on the wall members 22a and 28 opposite the control assembly 38. The

.armature arms I22 of the latches II1 are held in an open position relative to magnets I23 by a comb spring unit I28 carried by a bracket I 20 on the top wall 18 of the frame 28 and having a spring tooth I28 corresponding to and engaging an ear I3I on each latch II1. A comb spacing unit I32 of substantially U-shape (Fig. 3) is also carried by the bracket I20 and is provided with spaced teeth I35 each of which is adapted to be inserted between adjacent ones of the latches I I1 andon opposite sides of the shaft II8 to maintain the latches axially positioned on the shaft I I8.

The magnets I23 are electrically connected as 4 shown in Fig. 9 so as to be individually and secorresponding ccnductors'lic and common lead line I8I into the circuit of a motor I33 which drives the control shaft 21. Thus on pushing of a button I48 to the right as viewed in Fig. 9, a

corresponding magnet I23 is first energized by the closing of contacts I38a and I301), with continued movement of the button I48 toward the right closing the circuit for the motor I33 as will be later explained. The motor I33 is thus energized substantially concurrently with each of the magnets I23. On release of the button I48 it is evident that the motor will be deenergized prior to a deenersization of the selected magnet I23. The motor I38 is mounted within the frame means 20 opposite the inductance units Bic-Sic, and is operatively connected with the drive shaft 48 through gears I34 and I38, mounted on the drive shaft 48 and motor shaft I31, respectively (Fig. 1). The gear I38 is in driven engagement with the motor shaft I31 through a slip clutch which may be of any suitable type and is indicated generally as I38. The driving shaft 48 which also serves as the guideway for the guiding arm 4|, previously fully described, is provided with a toothed portion I38 near the end plate 28 for engaging the gear II2 on the control assembly 38. The motor I33, therefore, rotates the control member 21 through the above defined gear train. The motor is of reversible type and is diagrammatically illustrated in Fig. 9 as having a field F, the flow of current through which may be reversed by a reversing switch I assembled on the frame means 20 as a part of the tuning device and common to all of the latches I I1. Operative engagement of the switch I with each latch H1 is accomplished by the positioning of a spring switch arm I42 in a recess I40 (Figs. 3 and 7) formed at the end of the latch arm I2I near the tip portion I I8 thereof.

In the operation of the tuning device of Fig. l, and after the control rings 82 are each set to a predetermined angular position with reference to the shaft member 21, as will be explained, the peripheral portions 83 of the rings 82 and the friction discs 88 are compressed axially as an assembly and frictionally retained against movement relative to the flange 32 and hence to the shaft 21. With the control member assembly thus arranged. assume the latches ill to be in their rest positions so that the relative position of each latch and switch mechanism I is as shown in Figs. 3 and 10. The engagement of the switch spring arm I42 with the contact I43 indicates a position of the latch tip I I8 on the high side H of a control ring as indicated in Fig. 10. On closing of a push button I49, the magnet corresponding thereto and the motor I83 ar substantially concurrentl energized, rotation of the control assembly 38 being in a clockwise direction as indicated by the arrow in Fig. 10. By virtue of this direction of rotation the tip II8 0f the latch II1 passes over the recess R and upon the low side L of the control ring. On dropping of the tip II8 from the high side H to the low side L the switch arm I42 is moved out of engagement with the contact arm I and into engagement with the contact arm I, this arrangement of the switch mechanism III being indicated in Fig. 11. Referring to Fig. 9 it is seen that the closing of contacts I62 and I closes the motor circuit through conductor Ilia which is connected to one side of the motor field 1. with closing of contacts I62 and I connecting conductor Illa with the opposite side of the field 1" to close the motor circuit. Thus the action of switch I in response to the movement of the latch from the high. side H to the low side L of a control ring serves to reverse the how of current through the motor field F whereby to reverse the motor and hence the direction of rotation of the control assembly 36. Rotation in this reversed direction. indicated by the arrow in Fig. 11, continues until the stop II! at the recess R engages the tip II! as shown in Fig. 7.

n release of the selected push button I46 the motor and the selected magnet are deenergized, the selected latch being moved to a rest position by a corresponding spring I26 whereby the spring switch arm I62 is permitted to move out of engagement with the contact I and into engage ment with the contact I". Thus on later energization of the motor the switch Ill is set to provide for the rotation of the motor In in a direction which rotates the control assembly Ii in a clockwise direction as viewed in Fi 10. Of course, if a latch on energization of its corresponding magnet is moved directly into engagement with the low side L of a corresponding control ring 62, the contacts I62 and I will be immediately closed to provide for a rotation of the motor I33 in a direction to move the stop portion I I6 at the recess R directly into engagement with the latch tip I I6.

Before the control mechanism 31 is operated for tuning purposes described above, all of the control rings 62 or at least a number corresponding to the number of stations it is desired to tune, are set in predetermined angular positions corresponding to the tuning positions of the inductance units 6Ic-ilc for each of the desired stations. Insofar as the operation of the tuning device is concerned, it is to be understood that variable capacitance means may be utilized in place of the inductance units Ila-i l 0 within the teaching of this invention. It is evident, of course, that the capacitance tuning means, such a a variable condenser. would be operatively connected with the control member 21 so as to be operated thereby. Assuming that the screw 66 and its associated mechanism including the levers I01 are in a non-friction position, a selected button I66 is pushed in to complete the connections through contacts I3IIo--II6b and I360, to in turn energize a corresponding magnet I" and the motor I66. This causes the corresponding control ring 62, which is still held under a slight friction by the spring washers I II, to rotate until the tip III of the latch II1 drops into the recess R or the ring. The operator then either releases the button I46 entirely and returns it only far enough to engage the contacts 6a and Ilhb. or originally lets the button move out of engagement with contact IIIIc thus maintaining the magnet circuit closed and breaking the motor circuit.

With the selected push button I66 held to energize a corresponding magnet III, the control member 21 is manually rotated by an ordinary manual tuning knob at the radio receiver or at a remote control unit, the knob being operatively connected by a flexible cable or the like with a moulded coupling Ill secured to the driving shaft 66. This rotation of the control member 21 relative to the held ring l2 continues until the core elements I! are moved to a tuning position corresponding substantially to the signal frequency desired. With the core elements at this position the cam means 62 associated with each thereof is adjusted to in turn relatively adjust the cores 46 to eflect a matching or aligning of the inductance units at the tuning position. The predetermined matching of the units Slit-He at the desired frequency can be ascertained by listening, or by using an output meter. Alternatively the units Ola-lie may be matched in a separate and preliminary tuning operation in which the cams 62 are set to bring all or the circuits into alignment before final assembly. When this relative aligning of the inductance units 6Ia-6lc is completed the button I66 is released to open the magnet energizing circuit. It is understood. of course, that during this tuning operation that the contacts Inc-I600 for closing the motor circuit are open by virtue of the slight retraction of the push button out of engagement with the contact I360. The same procedure can be followed for each of the control rings 62. With a peripheral portion 68 of each ring separated from the peripheral portion of each other ring in the control assembly 36 by the axially yieldable but angularly fixed discs or separators 66, there is no possibility of any relative movement between a peripheral portion of the control ring 62 and the shaft 21, to cause any displacement of the control rings previously set.

When the setting operation for the rings 82 is completed the screw 66 is rotated so as to move the threaded support I06 outwardly from the cavity 61 or to the left as viewed in Fig. 1, whereby to pivot all of the levers I01 to compress the rings and separator discs of the control assembly against the annular flange 32. Although a screw with an ordinary slotted head is illustrated for turning by an ordinary screw-driver, it is apparent that a suitable knob can be employed for turning by band.

From a consideration of Figs. 1 through 4, it is seen that all of the defined elements of the tuning device are entirely enclosed within the confines of the frame means 20 and preassembled therewith as a complete unit without requiring any intermediate partition or supporting plates. The entire assembly is thus substantially open and readily accessible for assembly and servic- 8 P p s- In the modified form of the invention shown in Figs. 1%19, the tuning device is illustrated with both inductance and capacitance tuning means which are adapted to be operated simultaneously by a common driving means to vary the effective inductance and capacitance in the radio frequency circuit to predetermined values. As is shown in Figs. 12 and 15, the tuning device includes frame means having end walls IIil and I6Ia, side walls I62 and I62a, a base I66 and a top I64. A control member 21' is rotatably supported in the end walls IBI and I6Ia by adjustable thrust bearings I66, one end of the control member 21' having a cylindrical body portion I61 thereon and the other end I66 thereof carrying a control member assembly 36. The body portion I61 is formed on the periphery thereof with spaced spiral grooves I66 adapted to receive in mating engagement corresponding follower portions I68 (Fig. 18) provided on a slidable sleeve or driving member Hi. The sleeve member "I is integrally formed with an annular flange I12 having a radially extending bifurcated arm I13 for guidably engaging a drive shaft 48' arranged in spaced parallel relation with the control member 21' and rotatably supported in the end plates I6I and I6Ia. The annular flange I12 is connected by connectors I68 with the core against rotation but permitting movement thereof axially of the control member 21. It is seen, therefore, that all of the core elements 48' are initially set in a predetermined relative position which is maintained at all times by virtue of their direct connection with the slidable sleeve I'll. v

With reference to the schematic electrical circuit in Fig. 19 an inductance unit BI is illustrated as being included in the antenna circuit II, a first RF stage I52 and a first detector stage I58; the plate of the detector tube I54 being in series connection with the primary I55 of a first IF transformer, and the unit 5I' in the RF stage being in serie connection with the plate of the RF tube I56 and the control grid of the detector tube I54. The oscillator elements of the detector tube I54 are connected with the unit 5| in the first detector stage. Each unit 5| is electrically associated with a corresponding .variable capacitance unit I14 which is utilized in place of a usual padder condenser for a purpose to be now fully described.

Each condenser unit I14 includes adjustable cam means having an annular cam plate I16 with a peripheral portion thereof of about 180 being formed with angularly spaced radially extending blade elements I11 (Figs. 1 2, 13 and 14)- Concentric with the annular plate I16 and arranged on each side thereof against the blade elements I11 are flexible bronze rings I18 which are suitably secured as by rivets I18 to the plate I16 at an unformed portion thereof. The flexible bronze rings I18 are relatively thin so as to maintain a following relation with the sides of the blade elements I11. It is evident from Fig. 13, therefore, that any adjusting or deflecting of the blade elements I11 laterally of the plane of the plate I16 will correspondingly move the annular rings I18 laterally of the annular plate I16 to form a continuous cam surface over the bladed portion of the plate. The plate I16 is formed with an enlarged eccentric opening IN and an interlapping concentric opening I82, the

control member 21 being inserted through the opening I8I and into frictional engagement with the plate I16 by the seating of the plate at the opening I82 into a corresponding annular recess I83 formed in the control member 21, this construction being clearly shown in Fig. 14.-

Cooperating with each side of the cam plate I16 is a pair of condenser plates I84 and I85, each pair being operatively associated with one of the cam rings I18 (Fig. 13), and mounted at corresponding ends in a spaced relation on a bracket I81 supported on the frame base I68.

- ment' of the cam plate I16 of 180.

The leads I88 and I88 for the condenser plates I84 and I86, respectively, are shown in Fig. 14. Since each pair of plates I84 and I86 is similarly assembled relative to the cam plate I16, only one thereof will be described. The plate I84 is stationary and of a rigid construction while the plate I86 is adapted to be moved relative to the fixed plate I84. This moving of the plate In is accomplished by its operative connection'witn the cam ring I18 through an insulating contact or follower IIII provided at the unsecured end thereof. The plate I86 is arranged relative to the cam, ring I18 so that the follower I8I is always in engagement therewith. The effective rotation of the cam plate I16 is about 180, as indicated in Fig. 14 by the peripheral portion thereof formed with blades I11, and is commensurate to the total linear movement of a corresponding core element 48'. That is, the total linear movement of a core element 48'- in one direction will occur for an angular displace- The follower I8I, therefore, is always opposite a bladed portion of the plate I16. Thus, on rotation of the control member 21', the plate I86 is continuously moved relative to the plate I84 by virtue of its engagement with the cam surface I18, this back and forth movement of the plate I86 acting to continuously vary the capacitance of the condenser unit I14 to predetermined values. The condenser unit I14 is thus seen to be comprised of two condensers arranged in a balanced relation relative to a control member 21' and including a common adjustable cam I16. Be: cause of this construction and relative assembly of the unit 114, adjustments can be made on the' cam I16 without applying such unequal or disturbing forces on the shaft as would alter previously made adjustments elsewhere in the tuning device. It is to be understood, of course, that each pair of condenser plates I84--I86 may be connected together in either a series or a parallel relation.

In the operation of the tuning device of Fig. 12, it is contemplated that the capacitance effeet in the tuned circuits be complementary to the inductance effect therein and adjustable relative to the inductance effect to compensate for the ;usual inaccuracies and errors which occur in inductance tuning of permeability type and ance over a complete tuning frequency range.

Thus the core elements 48' of the inductance units ii are first set to relative fixed positions at the low frequency in a desired frequency tuning range, this fixed adjustment being accomplished by suitably securing the connectors I68 which connect the core elements 48' with the annular flange I12 of the slidable member I". With the core elements 48' retained at this initial fixed adjustment, the effective inductance and capacitance in the tuning circuit at certain intermediate tuning frequencies is varied through adjustment only of the capacitance by deflecting the blades I11 in each of the units I14 to change the capacitance of the condenser unit by a complementing amount sufficient to compensate for the error in the Inductance effect in the circuit at such certain frequencies. When the condenser units I14 have been thus adjusted at the certain desired frequencies over the entire frequency range, such adjustments will be retained on later rotation of the control member for both the capacitance units I18 and the inductance units 8|. Thecondenser units I18 are thus continuously adjusted to a predetermined value at each desired frequency concurrently with the adjustment of the cores 88 to relative tuning positions through the action of the cam plate I" and its associated cam surface I18 which serve to continuously vary the distance of the movable plate I88 relative to the stationary plate I88. Because of the simultaneous complementary variation of the effective inductance and capacitance values in the tuning circuit, high performance of a uniform quality is obtained over a complete tuning range.

The control member assembly, 38', in the control mechanism 31 for selectively rotating the control member 21' to control positions corresponding to predetermined tuning positions, is comprised of control rings 82 and separator discs 88 which are similar in all respects to the like parts described in connection with the embodiment of Fig. 1. The hub portions 88 of the rings 82 and the separators 88 are held together against axial and angular movement by screws I83 (Figs. l2 and '15) which are secured at one end to a plate I88 mounted in a fixed position on the control member 21'. The clamping of the circumferential portions of the discs 88 and of the peripheral portions 88 of the rings 82, is accomplished by means including a clamping plate I88 mounted for slidable movement axially of the member 21' and having apertures therein for loosely receiving the screws I83. The control member 21', at the end I 85 thereof, is formed with a threaded portion I8| which extends along the member 21' substantially to the outer end of the control assembly 38'. Threadably mounted on the portion I81 and engageable with the clamping plate I88 to move the same in a clamping position against the control assembly 88' is an adjusting nut I88 which constitutes a hub for a gear I88 in operative engagement with a gear 28I carried by the driving shaft 88'. Axial movement of the adjusting nut I88 in one direction on the member 21 is limited by its clamping position against the control assembly 88', while its axial movement in an opposite direction is defined by its engagement with a back stop 282 mounted at the extremity of the end I88 of the control member 21', a spring washer 283 being positioned between the nut I88 and the back stop 282 to provide a yieldable buffer for the nut I88.

The drive shaft 88' is provided with a manual control knob 288, rotation of which rotates the member 21' through the gears I88 and 28L On rotation of the control knob 288 in one direction, the member 21' rotates until a lug 288 formed on the plate I88 engages a stop 281 carried by the frame base I83. After this engagement the continued rotation of the knob 288 serves to axially move the clamping nut I88 along the control member 21' and against the clamping plate I88 to move the same against the control assembly 38. By virtue of this stopping of the control member 2'I- a positive clamping of the control rings 82, after a setting thereof, against angular and axial movement, is assured. Ball bearings 288 positioned intermediate the nut I88 and the clamping plate I88 reduce friction therebetween and provide for a tight clamping action. Of course, in some instances a brass washer or the like may be used in place of the balls 288. To unclamp the control rings 82, the control knob 288 is rotated in a reversed direction, the rotary member 21' rotating through substantially until a lug 288 arranged on the plate I88 diametrically from the lug 288engages the stop portion 281. This stop action permits the adjusting nut I88 to be loosened and axially moved against the back stop 282, this loosening being just sufficient to permit of a slight residual frictional holding pressure on the ring peripheral portions 83 by the separators 88 and plate I88. Clamping and unclamping of the control member assembly is thus obtained by utilization of the manual tuning means or control knob 288.

Cooperating with each ring 82 in the control assembly 38' is a corresponding latch 288 (Fig. 15), each of which is rigidly mounted at one end 2I8 on a bracket 2 carried by the top plate I88 of the tuning device frame means. Each latch 288 has a body portion 2I2 of substantially flat form with all of the latches 288 being longitudinally spaced with the body portions 2I2 in parallel relation. Each latch 288 near its supported end is formed with a recessed or cutaway portion 2I3, the curvature and extent of the recess 2I3 being such that the latch 288 is bendable in a direction substantially at right angles to the plane of the body portion 2I2. This bending of the latch 288 completely eliminates the usual lost motion which occurs through pivoted or like connections. The end 2I8 of each latch 288 is provided with an operating tip 228 which cooperates with the periphery of a corresponding ring 82 to control the rotation of the member 21 in a manner fully described above in connection with Fig. 1. Ability of the latch to bend at right angles to the body portion 2I2 thereof provides for a tip portion 228 which may be given any desired width for strength and rigidity purposes. Also similarly to the embodiment of Fig. 1, six latches 288 (Fig. 16) are illustrated in the present embodiment corresponding to the number of control rings 82 shown in the control assembly 38'.

Bending movement of a latch 288 in the operation of the control mechanism 31 is accomplished by a corresponding magnet 2I8 including an associated armature Hi, the armature being connected with the latch 288 through a strut or connecting member 2I'I. Each strut 2" (Figs. 15 and 17) is of substantially channel shape, having base extending portions 288 at each end thereof adapted to be bent into hooked engagement with apertures 288a and 2881: pro vided respectively in each latch 288 and armature 2I8, respectively. The magnets 2 are arranged in two parallel rows of three each, and mounted on a bracket 2| 8 of substantially U- shape which is supported on the top frame member I88. Each leg 2I8 of the bracket 2I8 carries a plate 225 (Fig. 16), each of which pivotally supports the armatures 2I8 corresponding to a row of magnets 2, the armatures having one end thereof in dove-tailed engagement with a corresponding plate 228. Each armature is normally held in an open position relative to its corresponding magnet by an associated coil spring 22I connected at one end 222 to a corresponding armature and at its opposite end to an armature supporting plate member 228.

The magnets 2 are electrically connected to provide for their selective energization by corresponding push button units 238. Thus as shown in Fig. 19, the magnets 2 are connected in parallel between power leads HI and 232 from the secondary 288 of a usual power transformer. Lead 28] is connected directly to the secondary 238 while lead 232 has a tuning motor 238 and "amin each of the magnets Ill.

The magnets 214 and armatures ill are 11- lustrated as adaptable for A. 0. operation. it late be understood. of course, that D. C. magnets and armatures may also betused. Each armature 210 on the side thereof opposite the pole motorswitchflleonnectedthereininserleswith lflismountedontheproiectingendofthemm.

therefrom. A slip clutch indicated generally as tor shaft I" and includes a pinion Ill in meshfaceofacorrespondlngmagnethasaplurality of flat springs III arranged thereon in a superposed relation and secured by a rivet 224 to one 10 end of the armature Ill. The springindicated as 2130 and positioned immediately adjacent the armature ll! extends outwardly from the other end of the armature for connection at the aperture llllrtherein with a corresponding end 15 "I of the strut or connecting member 211, the other end ill of the strut being connected directly to the body portion ill of a correspond- I ing latch "I at an aperture la. As is clearly,

ing engagement with a 8 2 carried by the shaft 48'. Since the shaft ll'also carries the assembly ment of such operating end. Cooperating with shown in Fig. 16 the extending ends of the so springs Ilia corresponding to oppodtely arranged armatures III are'faced toward each other so that all of the struts 211 are positioned 1 together in two adjacent rows to provide for their being connected with a corresponding latch 2", the latches being assembled transversely of the member 21' and spaced axially thereof across the control assembiyfl'. when a magnet l is energized, as by the closing of a push button 23., a corresponding armature 210 is immediately attracted to a closed position so as to eliminate any chattering action or hum regardless of the operating position of the latch tip 22. relative to the periphery of its corresponding control ring. In other words, the armature Ill moves to a completely closed position entirely independently of the position of the latch 2" relative to a corresponding control ring, with such closing action by virtue of the springs Ill and the flexibility of the latch Ill permitting the latch tip III to engage any part of the peripheral portion '3 of the control ring. On deenergization of the selected magnet 2 its armature II. is pulled to an open position by the action of the spring 221. During this movement to an open position, the armature engages the lowermost spring 2230 assembled thereon so that all of the springs I" and the armature iii are moved concurrently to positively move the latch tip 22. out of an engaging position with the recess R in a corresponding control ring. It is seen, therefore, that on closing of the armature the spring connection of the latch 20! therewith coacts with the initial tension in the latch to move the same into an e g in P sition with an associated control ring, while the latch on movement of the armature to an open position v is positively pulled out of an enga in P sition with the control ring because of the pick-hip actiosn of the armature 210 relative to the springs 22 As previously mentioned, the tuning motor 234 is arranged in the'circuit of the magnets 2H (Fig. 19) so as to be energised concurrently with each thereof. Similarly to the operation of the reversible motor 133 and control assembly 3 in e the embodiment of Fig. l, the motor 2 is also of reversible typ with reversing thereof being controlled by the switch unit I" in response to the moving of a tip 220 of a latch 20! from the high side H to the low side L of a corresponding control ring 82. with reference to Fig. 12 it is seen that the motor II is mounted on the end plate ll la of the tuning device frame means,

with the motor shaft 2 extending outwardly 7 theswitchunitlllintheoperationofthetiming motor I is a phasing condenser ill for controllingthemotortorqueanddirectionofrotation. 'Thuswiththelatchtip filridingonthe high side 1! of a corresponding control ring if. the switch arm 231 (Figs. 15 and 19), which -.is connected with lead 232 is in contact with a second switch arm I to close the motor circuit through conductor III. On movement of the latchtip flltothelowsldeLofthecontrol ring, the switch arm Ill moves into contact with a third switch arm I" and out of contact with thearmlfltothepositionshowninFlgslS and 19 to close the motor circuit through the conductor :41. The movement of the arm :11 is controlled through its engagement with a latch 2" at the recess 24: in the operating end thereof. It is evident, of course, that the closing of the motor circuit through the conductors 23! and "I reverses the current flow through themotortointurn reverse its direction of rotation. When the latch tip 22. drops into a corresponding recess R the switch arm III moves the third switch arm 2 into engagement with afourthswitcharmfll whichisconnected to the conductor 2. Since the switch arm 2" continues in contact with arm Ill, condenser I is shorted and current flows through both windings of the motor with the result that no torque is produced, and the motor "looks." The motor 234 is thus automatically stopped when a latchti'p drops into a recess R, the selected magnet remaining energiaed until its corresponding push button 230 is released.

. An off control button for the circuit of the radio receiver with which the tuning device is employed, is indicated at 241 (Fig. 19) for controlling a heater circuit 2 and a usual B circuit 2 including a rectifier tube "I. Power for the circuits 2" and I is supplied from a transformer III, the primary 252 of which may be connected to a suitable source of A. C. supply. The control button I" is connected by a conductor 2" with lead ill and a switch arm 254 of a power supply switch 25! which cooperates with the control assembly II to control the operation of the heater circuit I and B circuit 2". Referring to Figs. 12. 15, and 19, it is seen that the power supply switch 25! is mounted on the side plate I82 of the tuning device frame means and includes a gate member 2" common to the plates I94 and m of the control assembly I6 and having followers Ill and 2" adapted to fit within a corresponding recess Ill and I" on the periphery of the plates Ill and Ill, respectively. The common gate 2" is operatively associated with an A switch for the heater circuit including switch arms 201, 102, and the switch arm 254 connected with the "of!" button 241, and with a B switch included in the B circuit 249 and having switch arms 255, 254, and 255. As clearly appears from Fig. 12 the switches A and B form part of the structure of the power supply switch 255.

The recesses or notches 255 and 258 formed in the plates I94 and III, respectively, are in alignment axially of the control member 21' so that the follower portions 251 and 255 move in unison to operate the gate 255. When the'follower portions 251 and 258 are riding on the periphery of a corresponding plate, all of the switch arms corresponding to a switch A and B are in contact engagement to close their respective circuits as shown in Fig. 19. When the followers 251 and 258 are received in a corresponding recess 258 and 258, the gate member 255 is permitted to move inwardly of the emtrol assembly 85' and in turn permits all of the switch arms in a corresponding switch A and B to move to open positions, as indicated in Fig. 15, whereby to open their corresponding circuits. In the practice of this invention, it is contemplated that this open position of the switches A and B occur when the tuning means and I14 are in one of their extreme tuning positions.

This extreme tuning position is obtained by closing the o button 241 which sets up a circuit through conductor 255 and switch arms 254 and 252 to ground at G. Since lead 252 is also grounded at G, a circuit is established which causes the motor 284 to rotate in such a way as to rotate rings 82 and plates I84 and I85 in a clockwise direction as viewed in Fig. 15. This rotation continues until notches 258 and 258 reach buttons 251 and 258 opening the gate 255 and consequently opening the switches A and B to stop the motor and also open the circuits 245 and 248, thus turning the set off. The receiver is automatically turned on when any of the station buttons 258 are closed, since this rotates plates I84 and I85 to move the gate 255 to close the switches A and B as shown in Fig. 19. when turning the set on, it is only necessary, therefore, to press a push button corresponding to the station which is to be heard. On actuation of this push button the control mechanism 31' is operated to tune in the selected station and concurrently moves the followers 251 and 258 on the gate member 255 out of their corresponding recesses. The circuits 248 and 245 are thus simultaneously closed so that the radio receiver is automatically turned on with the pressing of a push button corresponding to the selected station. An individual power relay for oil and "on" operation is thus entirely eliminated, since the tuning motor 234 is used to operate the power supply switch 255.

Before the control mechanism 31' is operated for tuning, all of the control rings 52 are set in predetermined angular positions corresponding to the tuning positions of the inductance units II and condenser units I14 for each of the desired stations. In Fig. 12 there is shown a rotary dial 255 for indicating station positions, the dial being viewable through an aperture 251 formed in the panel 258 of the radio receiver. The dial is formed with a gear portion 259 for engaging a pinion 218 mounted on the shaft 48' and in frictional slip engagement therewith, spring HI and collars 212 and 218 acting as a slip clutch. With the adjusting screw I88 in a clamping position relative to the control member assembly 35', rotation of the manual control ill knob 284 to unclamp the control assembly 25' initially rotates the control assembly until the lug 288 engages the stop 281. The continued rotation of the knob 284 after this engagement serves to unclamp the control assembly 35'.

The dial 255 and the control assembly 25' are arranged for synchronous movement so that the control position of the control member 21' will always be properly indicated 'by the dial. Retention of this synchronous operation is accomplished by providing oppositely arranged ear or lug portions 214 and215 on the dial 255, which are adapted to engage a stop portion 215 provided on the end plate I5Ia of the tuning device frame means. The lugs 214 and 215 are arranged relative to the lugs 285 and 288 on the plate I54 so that the rotation of the dial 255 by the shaft 48', is stopped concurrently with the stopping of the control assembly 55'. The continued rotation of the shaft 48' to unloosen the nut Ill produces no rotative effect on the dial 255 by virtue of the slip between the pinion 218 and the shaft 48'. When the control assembly 25' is to be clamped the lug 215 on the dial 255 engages the stop 215 concurrently with the engaging of the lug 285 on the plate I54 with the stop 281. The synchronous relation between the dials 255 and the control assembly 25' is thus retained between the extreme limits of their movement, regardless of the indeterminate amounts at which the adjusting nut I58 may be rotated by the shaft 48' in the clamping and unclamping of the control assembly 55.

When the control assembly 25' is in a nonfriction position, setting of a control ring 82 to a predetermined angular position is accomplished by closing one of the push buttons 238, a peripheral portion 83 of a corresponding control ring 82 by virtue of the slight friction retained in the assembly 35' when it is in an open position, being rotated until the tip 228 of a corresponding latch drops into the recess R thereof. As previously mentioned, the dropping of the tip 228 in the latch R automatically stops the operation of the tuning motor 234. With the selected push button held down, the control knob 284 is rotated to indicate a desired station, the station being tuned in by simultaneous actuation of inductors 5I and capacitors I14, the capacitance units I14 being precisely adjusted as above described. The selected push button is then released. A similar procedure is followed in the setting of the remaining control rings, each ad justed control ring being held in a set position by virtue of the slight frictional engagement therebetween, and between the separator discs when the control assembly 55 is in a non-friction position. On adjustment of all of the control rings the adjusting nut I98 is moved by the operation of the manual control knob 284 into a clamping position. The control knob 284 thus functions to manually tune the radio receiver, scald to clamp and unclamp the control assembly Although the invention has been described with reference to several preferred embodiments thereof, it is to be understood that it is not to be so limited since modifications and alterations can be made therein which are within the full intended scope of the invention as defined by the appended claims.

I claim:

1. A tuning device having a plurality of inductance units therein, each of which has an adjustable core element, means common to all of rates of travel of said core elements to a tuning position so that said matched tuning relation is accomplished concurrently with their simultaneous movement by a driving means to said tuning P sition.

2. In a tuning device having a plurality of inductance units, each of said units having a linearly adjustable core element, control means common to said core elements and operatively connected therewith for simultaneously moving the same to a tuning position, cam means for each of said inductance units having a cam surface arranged substantially parallel to the path of movement of a corresponding core element, and a cam follower member carried by said control means and operatively connecting a cam surface with a corresponding core element. with each cam surface being adjustable transversely of the path of movement of a corresponding core element to relatively adjust the core elements to effect a matched tuning relation of said inductance units at each tuning position, and each of said followers on movement of said core elements to a tuning position c operating with an associated cam surface to vary the rate of travel of a corresponding core element relative to the rate of travel of the other core elements so that said core elements in said tuning position are relatively arranged to provide for said matched tuning relation of the inductance units.

3. Radio tuning apparatus including a rotary control member, means for rotating said control member to predetermined control positions, inductance tuning means having an adjustable core element linearly movable axially of said control member, means operatively connecting said core element with said control member including a slidable member mounted on said control member, andv means retaining said slidable member against rotation with said control member but permitting movement axially thereof, said rotary control member having a spiral groove in the periphery thereof and said slidable member having a follower portion adapted to be received in said groove, with said follower portion on rotation of said control member to a predetermined control position being moved along said groove to axially move said slidable member which in turn linearly moves said core element to a tuning position corresponding to said control position.

4. Radio tuning apparatus having a rotary control unit, a plurality of inductance tuning means, each of which includes a core element linearly movable'to a plurality of tuning positions over a wide frequency range, means for simultaneously moving said core elements in response to a rotation of said control unit including a sliding member common to said core elements and mounted on said control unit for slidable movement axially thereof, means retaining said sliding member against rotation with said control unit but permitting movement axially thereof, said control unit having a spiral groove in the periphery aseauo thereof icr receiving in following en a ement a follower portion provided on said sliding member, means operatively connecting each of said core elements with said sliding member, and an adjustable cam means operatively connected with each of said connecting means. with adjustment of a cam means linearly moving a corresponding core element to a tuning position relative to the other core elements, said follower portion and groove on rotation of said control unit .co-acting to axially move said sliding member, and a cam means and a corresponding connecting means cooperating to control the rate of movement of a corresponding core element to a tuning position in accordance with the predetermined adjustment of said cam means. k

5. In a tuning device having a plurality of inductance units, each of which includes a linearly adjustable core element, and means common to said core elements for simultaneously moving the same to relative tuning positions, the combination of means for individually adjusting a core element at a tuning position to provide foran aligning of said inductance units at said position including cam means for each of said core elements having a cam surface arranged substantially parallel to the linear path of movement of a corresponding core element, means for adjustably' varying the contour of said cam surface. means engageable with a cam surface and operatively connected with a corresponding core element to linearly move said core element in accordance with said cam surface adjustment. and means movably supporting said latter means on said common means so that each of said latter means on movement of said core elements to a tuning position is moved over a corresponding cam surface to in turn regulate the movement of a corresponding core element to its preadjusted position at said tuning position.

6. A tuning device for tuning a radio receiver over a wide frequency range including a radio frequency circuit having an inductance and a capacitance, with the effective inductance in said circuit being substantially greater than the efiective capacitance therein so that tuning is substantially accomplished by said inductance, means for adjusting said capacitance at each tuning position relative to said inductance to provide precision tuning characteristics of said circuit over said frequency range, with said adjustments being retained over said frequency range, said adjusting means comprising a rotary multipart cam with said parts being adjustable, a cam strip engaging said parts and varying in contour in accordance with the position of said parts, and a cam follower acting on said capacitance upon movement of said rotary cam and control means for simultaneously varying the effective inductance and capacitance values in said circuit to their predetermined values at each tuning position.

7. A tuning device for tuning a radio receiver including a radio frequency circuit with a plurality of inductance units therein, each of which includes an arfiustable core element, a capacitance unit in said circuit corresponding to each of said inductance units, movable means common to said core elements for retaining the same in fixed relative positions, a control member operatively connected with said common means to move the same and in turn simultaneously move said core elements to a tuning position, and adju'stable means for each of said capacitance units for changing the effective capacitance of said capacitance units at each tuning position to values which compensate for any misalignment in the tuning relation of said inductance units, and means operatively connecting said adjustable means and control member so that the elective inductance and capacitance values in said circuit are varied simultaneously to their predetermined values at each tuning position.

8. A tuning device having variable tuning means for a radio receiver including an "oil!" and "on" switch, rotary control means operatively connected with said tuning means, said rotary control meansincluding a drum portion with axially spaced recesses in the periphery thereof, a plurality of movable latches corresponding to certain of said recesses, with each of said latches having a stop portion thereon engageable with a corresponding recess to stop said control means at a predetermined control position, an actuating arm for said switch in operative engagement with said drum portion and having a follower portion thereon adapted to be received in one of the other of said peripheral recesses, said switch being in an off" position when said follower is in said one recess, and in an on" position when said follower is out of said one recess, with one of the control positions of said rotary control means providing for the dropping of said switch follower portion in said one recess, an operating magnet for each ofsaid latches operatively connected with a corresponding latch to move the same into engagement with a corresponding recess, motor drive means for said rotary control means, and push button means for selectively actuating said magnets to individually operate said latches, with actuation of a push button after the actuation of the push button corresponding to said one control position providing for a rotation of said rotary control means to some other control position so that said switch follower portion is removed from said one recess to automatically turn on said radio receiver.

9. A tuning device for a radio receiver including variable tuning means, with said receiver having an operating circuit including a control switch therefor, rotary control means operatively connected with said tuning means including a drum portion having peripheral recesses spaced axially thereof, a plurality of movable latches corresponding to certain of said recesses, each of said latches having a stop portion formed thereon, with said control switch including an actuating arm with a follower portion thereon engageable with said drum and adapted to be received in one of the other of said recesses, said control switch when said follower portion is in said one recess being adapted to open said operating circuit and turn off said radio receiver, said switch being closed and the radio receiver on when said follower portion is out of said one recess, operating magnet means for each latch for moving a corresponding latch into engagement with said drum, means for selectively actuating said magnets, and motor drive means for said rotary control means electrically connected with said magnets so as to be energized concurrently with each thereof, with rotation of said control means being stopped on engagement of the stop portion on a selected latch with a corresponding recess, one of said magnets and a corresponding latch being used to stop said rotary control means when the follower portion on said control switch actuating arm is in said one recess to provide for the opening of said operating circuit to turn off said radio receiver, with other of said operating magnets being moved from said one recess to close said switch and autom'atically turn on said radio receiver.

10. A radio tuning device including a plurality of inductance units each of which has a linear adjustable core element, control means for simultaneously moving said core elements to a tuning position, means for individually adlusting each of said core elements at said tuning position to align said inductance units, said adjusting means including a plate member supported in a position parallel to the linear path of movement of a corresponding core element,v

said plate having integrally formed blades spaced longitudinally thereof, fiat flexible means yieldably supported on said plate and extending across one side of said blades to form a continuous cam surface thereover, with adjustment of said blades laterally of said platevarying the contour of said cam surface, and a follower member for said cam surface pivotally supported on said control means, and having one portion pivoted to a corresponding core element and a second portion operatively engageable with said cam surface, with adjustment of said bladu moving said follower member to in turn linearly move its correspondin core element in accordance with said cam adjustment, with each of said core elements being always returnable to the preadiusted position at said tuning position by the cooperating action of a corresponding follower member and associated cam surface.

11. In a radio tuner having a rotary member for operative connection with radio receiver frequency changing means and having an assembly of a plurality of control members angularly adjustable on the rotary member and mounted near one end thereof, with said one end having a threaded portion, means for collectively clamping and unclamping the control members to the rotary member including a manual control member for rotating the rotary member, a clamping plate mounted at said one end of the rotary control member for axial movement against said control member assembly, a gear member having a hub threadable on the threaded portion of said rotary control member, means operatively connecting said gear member with said .manual control member, means engageable with said control member assembly to define the limits of rotation thereof, with rotation of said manual control member in one direction rotating said rotary control member assembly to one limit of rotation and tightening said gear member against said clamping plate to accomplish clamping of said control members, and rotation of said manual control member in an opposite direction rotating said control member assembly to the other limit of rotation and loosening said gear member to unclamp said assembly, and means frictionally engaging said gear member and rotary member to provide for the rotation of said rotary member by said manual control means when said control members are unclamped.

12. In a radio tuner having a rotary member for operative connection with radio receiver frequency changing means and having an assembly of a plurality of control members angularly adjustable on the rotary member near one end thereof, with said one end having a threaded portion, means for collectively clamping and unclamping the control members to the rotary member including a clamping plate axially movguano able on the rotary control member against one end of said control member assembly, a rotary adjustable member threaded on said threaded portion and engageable with said clamping plate, a manual control member operatively connected with said adjustable member to rotate the same, means confining the rotation of said control member assembly between two stop positions, with rotation of said manual control member in one direction rotating said control member assembly to one stop position and tightening said adjustable member against said clamped plate to accomplish clamping of said control members, and rotation of said manual control member in an opposite direction rotating said control member assembly to the other of said stop positions and loosening said adjustable member to unclamp said control members, means for indicating a tuning position of said frequency changing means, means operatively connecting said indicating means with said rotary control member including said manual control member, and means including slip clutch mechanism providing for a rotation of said indicating means concurrently with said rotary control member.

13. In tuning means including a slidable element and means for moving said element to a plurality of tuning positions, the combination of means providing for a precision adjustment of said slidable element at each tuning position including a fixed cam portion adjustable transversely of the path of travel of the slidable element, and a follower portion for the cam portion movable with said moving means and operatively connected with said slidable element, with initial adjustment of said cam portion at a tuning position acting on the follower portion to move said slidable element independently of said moving means, with the preadjusted position of said slidable element being retained on later movement of said element to said tuning position by said moving means.

14. In tuning means, the combination of means providing for the precision adjustment of a linearly adjustable element at each tuning position over a wide range of frequencies including an operating member for said element, a fixed cam portion having an adjustable surface substantially coextensive in length with the linear movement of said element, and a follower portion engageable with said adjustable surface and operatively connecting said operating member and element, with initial adjustment of the cam surface at a tuning'position acting on said follower portion to move said element independently of said operating member.

15. Tuning means including a linearly movable element, means for moving said element to a plurality of tuning positions, means providing fixed portion, and a movable portion carried on said moving means operatively connected with said element and in sliding engagement with said ilxed portion, with initial adjustment of said fixed portion at a tuning position acting on said movable portion to move said element independently of said moving means, with later movement of said moving means to a tuning position returning said element to a corresponding preadjusted position.

16. In tuning means including a tuning circuit having a longitudinally movable tuning element therein, the combination including rotary cam means having a spiral groove therein and means including a cam follower connecting said groove and said tuning element to move the latter upon movement of the cam means, and supplementary means for obtaining more precise tuning at each tuning position in said tuning circuit including a cam means having a cam surface, multi-parts individually adjustable to vary the contour of the cam surface, and a cam follower riding on said surface when said rotary cam means is operated, said supplementary means including said cam follower.

17. In. tuning means having a longitudinally movable tuning element and means for moving said element, the means providing for precision adjustment of the position of said element at various tuning positions over the path of movement including in combination a multi-part cam portion substantially coextensive in length with the path of \novement of said elenient, and with each of said parts being initially adjustable to provide all together a varied-surface path, and means operatively connecting said element, said means for moving said element, and said multipart cam portion including a follower movable over said varied-surface path formed by the parts of said cam portion.

18. In tuning apparatus having a tuning circuit, the combination including a longitudinally movable tuning element, means for moving the same, and supplementary tuning means comprising a variable condenser, and means for varying the capacity of said condenser having a portion operatively connected with said moving means, a plurality of adjustable portions, a cam strip engaging said adjustable portions having a cam surface corresponding thereto, and a cam follower operatively connected with said variable condenser.

HAROLD F. EILIUI'I'. 

